This invention relates generally to applicators for allowing a predetermined flow of a fluid for dissolving soluble substances and distributing mixtures to the fluid. The mixtures are formed inside the applicators by mixing the fluid with the soluble substances. The soluble substances can be in types of solid, solution or fluid. The most advantageous fields for using this invention are water sprinkler systems that provide nutrients for lawns, gardens or vegetable fields. Said applicators can be installed to existing Tee pipe fittings of pipelines of water sprinkler systems. The nutrients such as fertilizers, insecticides, or chemical compounds are placed inside the applicators. Their mixtures will be diluted into downstream flows of water in the Tee pipe fittings. It is to be understood that the scope of the invention is not limited to these fields presented hereinafter.